Safety tread



May 13, 1930. H. G; CHAPIN 1,757,992

SAFETY TREAD original Filed Apil 2v, 1929 @www 1MM wf 1Km/@M567 in;

Patented May 13, 1930 UNITED STATES PATENT ori-ICE HOWARD Gr. CHAPIN, OFBOSTON, MASSACHUSETTS; G. E .DWIN GHAIPIN AND J. ,CQLBY BASSETT,EXECUTORS OF SAID HOWARD G. CI'IAPIN, DECEASED, ASSIGNORS TO 'UNIZ-VERSAL SAFETY TREAD INC., OF LOWELL,

MASSACHUSETTS MASSACHUSETTS, A CORPORATION OFJ SAFETYY TREAD Applicationled April 27, 1928, Serial I\ To. 273,360. Renewed January 2, 1930.

This invention relates to a safety attachf ment for a stair tread,composed of a base plate formed to bear on the upper surface of thestair tread, and a slab of rigid anti- 5 slipping material secured tothe base plate and presenting a horizontal upwardly facing frictionalsurface with which the shoe soles of pedestrians Contact.

The chief object of the invention is to provide a safety tread, theantislipping surface of which is extended to project considerablyforward from the front edge of the stair tread, and thus increase thearea of said surface.

Of the accompanying drawings forming a part of this specification,-

Figure 1 is a perspective sectional view, showing a portion of myimproved safety tread.

Figure 2 is a perspective sectional View, showing only the Abase plateand its channelled flan e.

Figgure 3 is a sectional elevation, showing the safety tread in itsoperative position on a stair tread.

Figure 4 is a fragmentary view similar to a portion of Figure 3, showingthe eect ofv wear.

The same reference characters indicate the same parts in all of thefigures.

In the drawings, 12 designates a flat base plate of sheet metal, formedto bear on the upper surface of a stair tread 13. Formed integral withthe base plate is a substantially U-shaped channel located at theforward portion of the plate. Said channel is composed of an inner wall14:, projecting downward from the plate 12, and formed to overlap andbear on the outer edge of the tread 13, a neck 15, projecting outwardfrom the inner wall, and an outer wall 16, projecting upward from theneck and spaced from the inner wall, so that' the channel has an openmouth. A slab of antislipping material, whichmay be any of thecompositions or mixtures usually employed in safety treads, is appliedto the plate and channel w iile in a soft or plastic condition, andsubsequently hardened. Said slab includes a body portion '17 whichcovers the plate, and a rib portion 170, which lills the channel. Theslab may be anchor-ed in any suitable way, so that when hardened, it isfirmly secured to the plate.

The exposed wear-sustaining surface of the layer includes an upwardlyfacing top face' 1'711 extended forward over the rib portion 17c and aforwardly facing edge face 17h extending downwardly from the forwardportion of the top face to the outer wall 16 of the channel. inforced bythe channel, and the face 17b extends continuously from end to end ofthe safety tread, and constitutes an antislipping extension of the topface 17 a.

It will be seen that the projecting forward l portion of the slab isthickened by the rib 17C, so that it is adapted to sustain maximum wearon the edge face 17 b and on the forward portion of the top face 17a, asindicated by full and dotted lines in Figure 4, the full linelindicating the edge face after it has been worn away to a considerableextent. The wear thus indicated does not objectionably weaken the slab,and does not objectionably reduce the area of the antislipping surface,Vbecause of the presence of the rib.

The faces 17 a and 1'7b meet to form a salient wear-sustaining shoulderabove the channel.

1t will also be seen that the forward projection of the slab and channelfrom the outer?" stair tread, and comprising a metal base plate;v`

formed to bear on the top of the stair tread and having a downwardlyprojecting channel adapted to project forward from the outer edge ofsaid tread, said channel including a downwardly projecting inner wall,formed4 to bear on said outer edge, an outwardly projecting neck, and anupwardly projecting outer wall spaced from the inner wall; and a slab ofrigid antislipping material covering the base plate and including adownwardly projecting rib lling the channel, an upwardly facing top faceextended forward over the rib, and a forwardly facing edge faceextending downward from the top face to the outer wall of the channel,said faces meeting to form a salient wear-sustaining shoulder, theforward portion of the slab being thickened by the rib and shoulder, andadapted to project forward from the forward edge of a stair tread towhich the safety tread is ap plied, to extend the antislipping surfaceforward from the stair tread, the thickened projecting portion of theslab being supported by the channel portion of the base plate.

In testimony whereof I have affixed my signature.

HOWARD G. CHAPIN.

